Carburetor



June 2, 1931. E. M. FABRIZI ET AL;

CARBURETOR Filed Aug. 8. 1929 INVENTOR ATTORN 5Y5 Patented June 2, 1931 UNITED STATES PATENT OFFICE,

ERNANI M. FABRI ZI AND GI'USEPPE BERTI, OF DETROIT, MICHIGAN, ASSIG-NORS OF ONE-THIRD TO VINCENT GIULIANO, 015 DETROIT, MICHIGAN cA BUnn'roR Application filed August 8, 1929.

This invention relates to devices for producing combustible charges for internal combustion engines, and more particularly to a device known as a carburetor wherein air and fuel inlets are controlled and a mix ture of air and fuel is produced by engine inspiration. I

An object of the present invention is to provide a carburetor of simple construction embodying a minimum number of parts so arranged and constructed as to minimize the liability of getting out of order. A further object is to provide a construction wherein the inlet of air and therefore the proportion of air to fuel, is regulated by the speed and consequent suction of the engine, and further to provide means whereby an andequate explosive mixture will be provided at very low engine speeds, giving high power at such speeds. It is also an object to provide means whereby the proportion of fuel to air may be accurately adjusted to give a lean or fat mixture, according to atmospheric conditions, and it is also an object to provide a simple arrangement of parts whereby these parts may be quickly disassembled for replacement or repair, and to provide certain other new and useful features in the construction and arrangement of parts, all as hereinafter more fully set forth.

With the above and other ends in View, the invention consists in the matters hereinafter set forth and more particularly pointed out in the appended claims, reference being had to the accompanying drawings in which Figure 1 is a longtitudinal vertical section through a structure illustrative of an embodiment of the present. invention;

Fig. 2 is a vertical transverse section substantially upon the line 22 of Fig. 1; and

Fig. 3 is a cross sectional detail upon the line 33 of Fig. 1.

As illustrated in the accompanying drawings, a casing l is provided, said casing being cored out to form a float chamber 2. and an air inlet chamber 3 which opens through the bottom of the casing, said Serial No. 384,261.

chamber 2 opening through the top of the casing and being closed by a cap 4.

Mounted upon the casing 1 is a head 5. said head being cored out to form an outlet passage 6 leading to the engine or engine manifold to which the carburetor is to be attached by means of cars 7 extending laterally from the upper end of the tubular passage 6, and provided with openings to receive bolts for securing the carburetor to the manifold (not shown). The head 5 is cored out at its lower end to form a mixing chamber 8, and this chamber extends laterally from the lower end of the passage 6 and is provided with an end wall having small air inlet holes '9 which open into an air chamber 10 formed by atransverse wall 11 having a single air inlet opening 12 which 'is controlled by an adjusting screw 1-3 screwed into an opening through the outer wall with the head of the screw in exposedposition so that the adjusting screw may be adjusted into or. out of the air inlet opening 12 to regulate the amount of air which will pass therethrough into the mixing chamber 8.

The usual throttle valve 14 is provided within the outlet passage 6 for controlling the outlet of. explosive mixture to the engine and thereby controlling the speed of the engine.

The top Wall 15 of the casing 1 forms a bottom closure for the mixing chamber 8, and within this wall is an opening 16 which is formed to provide a seat for an air valve 17, said air valve being adapted to be lifted by suction created in the chamber 8, upwardly into said chamber, and open a passage for the'flow of air from the air chamber 8 past said valve into the chamber 8. This valve 17 is guided in its movement by means of a tubular stem 18, which tubular stem is sleeved upona post 19 extending upwardly from a bottom wall of the casing 1 with its upper end within the opening 16 axially thereof. The sleeve 18 is free to slide upon the post 19 and is limited in such sliding movement b ..means of a transverse pin or shaft 20 which is rotatable within a transverse bore in the post, and extends through longitudinal slots 21 in opposite sides of the sleeve 18. The longitudinal movement of the sleeve, and therefore the lifting movement of the valve, is thus controlled or limited by the ends of the slots 21 coming into contact with the pin 20.

Fuel from the float chamber 2 is conducted into the mixing chamber 8 for a mixture with the air passing into said chamber past the valve 17, by means of a passage 22 leading from the bottom of the float chamher to a point directly beneath the post 19, and this post is bored longitudinally or formed with a small passage 23, which passage opens through the upper end of the post 19 and is intersected by the hole in the post within which the pin or rod 20 is located. This rod 20 has end bearings in the lateral side walls and is provided with an indi axing hand wheel 24 having an indicating portion movable over markings to indicate. the position. to which the rod turned, and this rod is formed with a transverse opening 25 which, in one position of the rod, is in alignment with the passage 23 in the post. By turning the rod the passage 23 may be restricted, the rod with the opening 25 therein forming a valve to regulate the flow of fuel through the passage 23, and thus regulate the amount of fuel entering the mixing chamber to mix with the air therein. Therefore the strength of the combustible mixture passing to the engine may be accurately regulated by turning the rod or valve, and the position of the valve is indicated exteriorly of the casing by means of the indicating hand wheel upon its outer end.

Fuel is conducted to the float chamber through a supply pipe 26 which has a cupshaped head 27 on its end to fit over a hol low boss 28 extending downwardly from the bottom of the casing, said boss being formed with lateral openings 29 to permit the flow of gasoline from the head 27 into the central bore of the boss, which central here is closed at its lower end, by a plug 30 screwed into the bore, and the upper end of which bore is reduced to form a passage 31 opening into the bottom of the float chamber. To prevent sediment or other matter carried by the gasoline from entering the float chamber, a wire screen 32 is placed within the cup 27 between the inlet pipe 26 and the openings 29, and the flow of gasoline into the float chamber is controlled by a valve 33 on the lower end of a rod 3 L which passes loosely through an axial opening in a float 35 located within the float chamber. Said rod 34 extends upwardly through the cap 4 and is guided therein for free longitudinal movement, and this rod carries a transverse stop pin 36 which is adapted to be engaged by the float as the float is raised by accumulation of gasoline in the float chamber, and thus raise the rod 34, bringing its valve 33 into seating on gagement with a seat at the lower end of the passage 31. Therefore the level of fuel in the float chamber is maintained at all times by the automatic opening or closing of the valve 33 operated by the float In operation, when the engine is started and suction created in the outlet passage 6 by the operation of the engine pistons, fuel is drawn up into the chamber 8 through the passage 23 and mixes with air entering through the air holes 9, and thence into the chamber through the inlet 12, its quantity being regulated by the regulating screw 13.

t very low engine speeds when the suction is not suflicient to raise the valve 17 from its seat, a very rich mixture is thus provided in the mixing chamber 8 to supply the engine and give power at low speeds.

As the speed of the engine is inereasml,

thus increasing the suction, the valve 17 will be lifted from its seat and additional air will be drawn from the air chamber 3 past the valve. This air will mix with the fuel supplied through the passage 23 which is open at its upper end into the mixing chamber, and as the amount of air admitted past the valve 17 is regulated by the speed of the engine, the greater the speed the greater will be the quantity of air admitted to the chamber, thus varying the strength of the mixture according to the speed of the engine.

The amount of air drawn in at high speeds past the valve 17 from the air chamber 3, may be regulated by means of an air valve 37 positioned within the inlet to the air chamber. This air valve may be operated by any suitable means in order to further regulate the combustible mixture supplied to the engine, and thus regulate its speed and power.

Obviously changes may be made within the scope of the appended claims, in the construction and arrangement of parts and passages, without departing from the spirit of our invention, and such changes in the construction and parts or their mechanical equivalent, are contemplated.

Having thus fully described our invention, what we claim is 1. In a carburetor, the combination of a casing formed with a float chamber and with an air inlet chamber, means for supplying fuel to the float chamber, means regulating the flow of fuel into the float chamber including a float, a member forming a mixing chamber positioned above the air chamber and communicating with said air chamber through an opening in a wall of the casing, said opening providing an upwardly facing valve seat, an air valve to seat on said seat, a tubular sleeve on the air valve, a post fixed in the casing with its upper end extending through the opening in the casing wall which affords communication between the mixing chamber and the air chamber, said post being formed with a restricted fuel passage extending axially therethrough and opening at its upper end into the mixing chamber and communicating at its lower end with the fuel chamber, and a valvular member extending transversely through said post and interrupting said fuel passage, said valve sleeve being formed with elongated openings in opposite sides thereof through which said valvular member extends.

2. In a carburetor, the combination of a casing formed with a float chamber at one end and an air chamber at its opposite end open to the atmosphere, a head on the casing forming a mixing chamber above the air chamber and having an outlet passage for the discharge of combustible mixture from the mixing chamber, a throttle valve in said outlet passage, a wall separating said mixing chamber from said air chamber and provided with an opening formed with an upwardly facing valve seat surrounding the opening, a post extending vertically across the air chamber with its upper end extending through the opening in said wall and formed with an axial fuel passage opening through the upper end of the post into the mixing chamber and communicating at its lower end with the float chamber, an air valve for closing said opening, a tubular sleeve on said air valve slidable upon said post for guiding said valve, said sleeve having elongated openings in opposite sides thereof, a rod extending transversely of the post through a transverse opening therein cutting through said fuel passage, said rod having a transverse opening to align with the fuel passage in one position of its turning movement, said rod forming a valve to control the flow of fuel through the fuel passage and extending through the elongated openings in the guide sleeve for limiting the upward movement of the air means for admitting air to the mixing chamber and comprising an air inlet opening in a wall of the mixing chamber and a regulating screw for controlling the passage of air through said inlet, an air throttle valve for controlling the admission of air into the air chamber, and a fuel supply pipe for said float chamber.

In testimony whereof we aflix our signa tures.

ERNANI M. FABRIZI. GIUSEPPE BERTI.

valve, auxiliary air inlet 

